Many Forts, Many Uses

in South Boston

Today’s Fort Independence, completed in 1851, is Castle Island’s eighth fort.

Engraving courtesy of the Boston Public Library, Arts Department

Castle Island’s strategic position alongside the narrow deepwater channel into Boston made it an ideal location to deter attacks. English colonists built the island’s first fort in 1634. They used what was readily available—timber and mud. Each fort that followed was sturdier than the one before. The present one is made of granite from Rockport, Massachusetts.

The island served a mix of military and civilian roles. Religious dissenters, deserters, and convicted criminals were among those imprisoned here.  British officials and soldiers took refuge here from outraged Bostonians in the 1700s. The island was Boston’s inoculation facility during the 1764 small pox outbreak. And during World War II, Castle Island served as the location where the Navy demagnetized hundreds of U.S. warships to protect them from the enemy’s magnetic mines.

In 1962, the federal government transferred the fort and island to the Commonwealth of Massachusetts. Fort Independence is managed by the Department of Conservation and Recreation and is open on select summer days, with tours offered by Castle Island Association volunteers.

In March 1775, Prince Hall and 14 other men of color were inducted into a British Army Lodge of Freemasonry likely at Castle Island. Nine years later they formed the first Masonic African Lodge in the U.S.  One of the most influential African-American activists of the late 1700s, Prince Hall advocated for an end to slavery and equal treatment for persons of color, notably in a widely published speech.

Cover of Prince Hall’s published 1797 speech courtesy of the Library of Congress

During the Civil War, barges brought cannon manufactured at South Boston Iron Company to be tested on the island. Union recruits also trained here.

Engraving by George H. Hayes, courtesy of the Boston Athenaeum

Castle Island was once truly an island surrounded by shallow water except along its north shore where a channel led into the harbor.

1776 map courtesy of the Norman B. Leventhal Map & Education Center at Boston Public Library

Sign Location

More …

1st Fort: 1634-1643

2nd Fort (the pine tree fort) 1644-1652

3rd Fort: 1653-1673

4th Fort: 1674-1701

These first four forts were referred to as “The Castle” and all were built by the Massachusetts Bay Colony.

5th Fort: 1701-1776 “Castle William” built by the British Army

6th Fort: 1776-1801 built by what would become the Commonwealth of Massachusetts

7th Fort: 1801-1834 “Fort Independence,” the first US Army fort, built by the US Army Corps of Engineer

8th (current) Fort: 1834 to present “Fort Independence,” the second US Army fort, built by the US Army Corps of Engineers

Source: Reid, William J. Castle Island and Fort Independence. Trustees of the Public Library of the City of Boston, 1995.

March 20, 1776, British forces leaving Boston blew up Castle William. Americans refortified the island. In 1799 President John Adams visited Castle Island and announced that in the future the fort would be known as Fort Independence.

The armament varied. In 1635, there were just three cannons; by the 1770s there were more than 200. When the fort underwent its last major modifications in the late 1860s/early 1870s, the ramparts were redesigned to accommodate the 15-inch smoothbore, 50,000-pound Rodman cannon. Water batteries on the east and west sides of the island added to the Fort’s armament.

Source: Castle Island Association brochure, “Castle Island Fort Independence.”

“Since 1634, the eight forts on Castle Island were involved in only one hostile action. In March 1776, after occupying Dorchester Heights, the Patriots moved to erect a redoubt—a small fort—on what is now Farragut Road, so they could fire at ships in the channel. British forces at Castle William responded by firing cannons from the island, but the range was too great. Colonial troops ignored the shell fire.”

Source: Castle Island Association brochure, “Castle Island Fort Independence.”

Families lived on Castle Island intermittently, depending on whether the country was at war and the type of troops stationed here. The first family to live here stayed for 20 years (1645-1665). In 1809, 50 children resided on the island with their parents. The last family to live here was the Lindbergs for whom the commandant’s house was home from 1914 to 1948.

Source: Reid, William J. Castle Island and Fort Independence. Trustees of the Public Library of the City of Boston, 1995.

By 1870, approximately 20 buildings stood on the island, in addition to the fort itself. When the federal government transferred the island and fort to the Commonwealth of Massachusetts in 1962, the only original structures remaining from that period were the Commandant’s Quarters (which burnt down in 1963) and the water batteries and magazines which the state leveled in 1964.  The Signal Corps Building, originally known as the Army Radio Transmitting Station, was built in the 1920s and can be seen near the playground.

The number typically varied from 150 to 270 men, plus an unknown number of nonmilitary personnel.

Sylvanus Thayer (1785-1872) began his military career as a second lieutenant in the Army Corps of Engineers. He is likely best known as the “Father of West Point,” for having transformed the institution during his 16-year tenure as superintendent. Following his service there, Thayer once again resumed his role as engineer. He supervised the construction of both Fort Warren (on Georges Island) and Fort Independence. Sylvanus Thayer funded both Thayer Academy in Braintree, MA, (where he was born) and Thayer School of Engineering at Dartmouth College (where he received his degree).

From 1634 when the first fort was built until 1879 when the current fort was decommissioned, Castle Island was the oldest continuing fortified site in British North American.  The forts on Castle Island protected Boston during all wars from colonial times through the Civil War.  After decommissioning, the fort was reactivated for various purposes during the Spanish American War, World War I and World War II.

  • In July 1665, the fort’s commanding officer, Captain Richard Davenport was killed by lightning while resting in his room. The lightning bolt missed a powder magazine by just a few feet.
  • Stephen Burroughs, a counterfeiter imprisoned at the fort in the late 1700s, is considered the most famous prisoner, in part perhaps because he wrote about his confinement on Castle Island in his memoir.
  • After the passage of the Stamp Act of 1765, the stamps shipped from England to Boston were held at the castle for safe keeping and never made it to shore.
  • Paul Revere of Longfellow’s midnight ride fame and a Son of Liberty served as the commandant of the fort on Castle Island from 1776 to 1780.
  • Christmas Day 1817, 21-year-old Lt. Robert Massie was killed in a duel with Lt. Gustavus Drane on Castle Island. Drane was brought before a court-martial, but was acquitted due to lack of witnesses. He remained in the army for a number of years after the duel and died in 1846.
  • In 1827, Edgar Allan Poe served for five months at Fort Independence under the alias Edgar Allen Perry. Legend has it he based his story, “The Cask of Amontillado” on tales told about the aftermath of the duel.
  • Fort Independence served as a torpedo and mine station during the Spanish American War. In 1898, while removing mines from Boston Harbor after the end of the war, an accidental explosion killed four soldiers and demolished the southeast corner of the island.
  • Joe Maguire, 1897 National Single Sculls Champion, learned the sport by rowing to school in South Boston from Castle Island where his family lived when his father was the US Army Ordnance Sergeant at Fort Independence.

Resources

  • Allen, Danielle S. “A Forgotten Founder,” The Atlantic, March 2021.
  • Bowen, James. Massachusetts in the War, 1861–1865. Clark W. Bryan & Co., 1889.
  • Cary, John. Joseph Warren: Physician, Politician, Patriot. University of Illinois Press. 1964.
  • Forman, Samuel A. Dr. Joseph Warren: The Boston Tea Party, Bunker Hill, and the Birth of American Liberty. Pelican Publishing Co., 2012.
  • Gregory, A. F. Historic Fort Independence and Castle Island. Press of Louis F. Weston, 1908.
  • Horton, James Oliver. Free People of Color: Inside the African American Community. The Smithsonian Institution, 1993.
  • Horton, James Oliver and Lois E. Horton. Black Bostonians: Family Life and Community Struggle in the Antebellum North. Holmes & Meier, 1999.
  • Reid, William J. Castle Island and Fort Independence. Trustees of the Public Library of the City of Boston, 1995.
  • Schouler, William. A History of Massachusetts in the Civil War. E. P. Dutton & Co., 1868.
  • Snow, Edward Rowe. Castle Island: Its 300 Years of History and Romance. Andover Press, 1935.
  • About demagnetizing or degaussing http://indicatorloops.com/usn_pequot_magnetism.htm

Acknowledgments

This sign is made possible by funding from a Boston’s Community Preservation Act grant.

Warm thanks to historians at the Castle Island Association for their guidance and expertise in creating this sign and to the Department of Conservation and Recreation for their partnership.

Thank you to Brendan Albert and Kate Gutierrez for generously funding Spanish translations for the Castle Island/Pleasure Bay signs.

Our gratitude to the Perkins School for the Blind and David W. Cook for their partnership in creating the audio files.